How do implement the effect of blur on transparent materials?
A very simple solution is to create a render pass for the glass and use it as a mask to add blur in the compositor. Of course, to implement the depth effect, you would also then need to render out a depth mask to use as the blur amount, and then your passes are adding up. That's a lot of rendering and compositing just to avoid a glass material, but this method can sometimes end up rendering faster because it avoids some of the typical issues associated with rendering glass.